When Good Vibrations threw a 25th anniversary party in December, porn star Nina Hartley, performance artist Annie Sprinkle, supervisors Tom Ammiano and Mark Leno, the Extra Action Marching Band, the Sisters of Perpetual Indulgence and about 1,500 other celebrants were all there to wish the Bay Area institution a big, wet, sloppy, happy birthday.

The founder of the sex toy store, Joani Blank, was also in attendance, but most of the partygoers didn't recognize the 65-year-old, gray-haired matriarch with the gently lined face. She wasn't easy to find in any case - she spent most of the evening in the VIP room trying to escape the thundering music.

"It was very loud," she said. "I don't get it about loud music."

Eventually though, she tired of lurking in the background, and the good-sex grandma made her way to the stage, where emcee Carol Queen introduced her. She waved and blew kisses before disappearing again into the throng.

"I was diffident, modest and shy," she said.

Modest? Shy? Joani Blank? This is the explosive spirit who began selling sexual aids to women in March, 1977 - not exactly the halcyon days of the vibrator. She mirthfully introduced thousands of women to sex-toy joy - expanding the business from a closet-size enterprise - then turned around and sold the company to the workers. In senior citizenry, Blank is as gung-ho about sexual freedom as ever. When she's not running around filming people in sexual thralldom (indeed, that is one of her upcoming projects), she's rhapsodizing about one of her other great loves: co-housing, electric cars, singing, the Unitarian Church, the artist Jan Saudek and her toy poodle, Bapu- ji.

"She's crazy," said Leigh Davidson, longtime managing editor of Down There Press, the Good Vibrations book publishing house that Blank founded in 1975. "Who else in the 1970s would decide to sell vibrators? But I think all visionaries are crazy; that has to be part of their definition."

David Steinberg, an author and fellow sex evangelist, met Blank at a book conference almost 30 years ago - she was wearing a T-shirt emblazoned with the Down There Press logo and a giant arrow pointing south.

"Joani is a big package to handle," he said. "She has all this energy, and if it doesn't interest you or it's too much for you, then Joani's going to be too much for you. She's a lot. She's going all the time. She has all this energy, all these opinions, and she'll tell you about it."

Snuggling with her Bapu-ji during an interview in her downtown Oakland co- housing unit, Blank insisted that she is in fact shy, no joke. But after talking it over, (and talking and talking; she likes to talk), she came around to a different description of herself.

"I take up a lot of space. I'm not proud of this," she said finally. "I haven't been able to figure out how to be smaller without diminishing myself; how to make space, psychic space, for other people.

"I feel bad when I walk away from conversations and think, "I didn't find out much about the other person.' It's not that I'm not interested or that I didn't ask questions.

"It's just that my story seems bigger than theirs."

Blank grew up in the Boston area, attended Oberlin College in the '50s, traveled in India and other parts of Asia for a year, studied public health at University of North Carolina, worked in family planning for several years, then began scheming about how to get to California. Finally, she figured: Why scheme? Just go. So she did.

A stint at Planned Parenthood led her to a volunteer position at the nonprofit San Francisco Sex Information, which led her to a job as a sex counselor at UCSF, where she led groups for pre-orgasmic women.

"Essentially," she said, "they learned how to masturbate." For those who did the homework, the success rate was very high.

The idea for the store came to her around that time.

"I encouraged women to try vibrators," she said. "So I just thought there should be a non-sleazy place for people to buy vibrators. It's that simple."

Blank invested $4,000 of her savings to open a 200-square-foot shop in the Mission District - the second such women-oriented sex toy shop in the country. (The first, Eve's Garden, is in New York City.) She put her antique vibrator collection (the oldest dating to the turn of the century) on display and set out a dozen, maybe 18 items.

"I don't think we even had lube," she said. Most days, she grossed around $40 in sales; on a busy Saturday, she would hit $100. Customers left with bags that read "plain brown wrapper."

"You'd walk into Good Vibrations, and Joani would be sitting there behind the counter," Steinberg said. "It was like walking into someone's living room, almost."

Business hummed along, too. The store grew. Blank hired more staff. They moved into progressively larger spaces, added an 800 number and started a mail- order catalog. Over the years, the stock has expanded to include videos, books and gear for sadomasochism practitioners, as well as men who prefer sex- shopping in a bright place with informed salespeople.

Throughout the changes, Blank fancied herself the conscience of the business rather than a profit-driven entrepreneur. "My vision is a different kind," she said. "Not to sell X number of videos or vibrators; it's about giving people more options to express themselves sexually."

Even former employees who found Blank's oversize personality a workplace hazard said they admired her unwavering commitment - above all - to a more-the- merrier mission. A decade ago, when Rachel Venning and Claire Cavanah decided to start a similar business in Seattle, they cold-called Blank, who opened up her store and her financial books to them.

"She believes in that message of getting sexual information out to people and was not at all competitive. I really see her like a missionary," said Venning, who has since opened a second Toys in Babeland shop in Manhattan. "They wouldn't do that now. We wouldn't do it. Especially with Internet age, the industry has become more directly competitive."

Blank had always been drawn to democratic management - workers, for instance, set their own salaries. At her urging, the company leaned further toward self-governance until Blank took the final step and offered to sell the business to the employees. With the help of a lawyer, the staff worked out a cooperative model and bylaws: Although something akin to management hierarchy exists, worker-owners vote on major issues and elect a board of directors; after a short period - recently changed to six months - workers have to buy in;

a percentage of profits are paid to owners equally according to the number of hours they worked. The sale was completed in 1992 for a sum Blank declined to disclose. (A Good Vibrations spokesperson said it was under $1 million.) Fourteen people became worker-owners.

Blank stuck around as a co-owner for a couple of years but finally (some former employees suggested that giving up control was harder than she'd imagined), she left altogether. She still has a title - publisher emerita - and gets a store discount. She also continues to collect from the buyout which was set up to be paid out over 20 years.

In the years that have passed, the industry has grown dramatically, with help from the Internet and a generally more sex-positive culture. Good Vibrations has thrived apace: The company, Open Enterprises Cooperative Inc., has video and audio production houses, stores in Berkeley, the Mission District and - since January - on Polk Street. There are now 105 employees; 78 are co-owners. Annual sales are $10 million-plus and continue to grow despite the sluggish economy.

She could have been an extremely rich woman - people frequently say that to her - but Blank shrugs it off.

"At some point, you stop changing your kid's diapers because they can put their panties on on their own," Blank said.

Her daughter, she pointed out, was born the same year as the store and it somehow made sense that they both established independence at the same time.

"I had two teenage children. One was the store and one was my actual teenage daughter. I didn't want any teenaged children. It was time for them to be on their own."

Right after the sale, Blank's daughter left for boarding school. She became a mother herself, at age 16.

"It was a rebellion in some ways, but an unconscious one," said Amika Sergejev, now 25 and a midwife in Portland.

"It changes over time what it's like being Joani's daughter . . . It was harder early on having your mom be in the sex business," she said. "Now, of course, I'm so grateful for the way I grew up."

Blank's to-do list, once legendary among friends for its length, still rambles on and on - even as she has started collecting Social Security. She's the author or editor of nine books and shows few signs of letting up. Among her oeuvre: "The Playbook for Women about Sex," "The Complete Guide to Vibrators," and "First Person Sexual: Women and Men Write About Self-Pleasure, " "Still Doing It: Women and Men over 60 Write about Their Sexuality" and "Femalia," a collection of photos of vulva.

(Don't dare call them vaginas. "We're really cheating our daughters by teaching them that their genitals are their vaginas," said Blank, who considers it a feminist issue. She even went up against Eve Ensler - the creator of "The Vagina Monologues" - on this one, confronting her about the vulva issue after a show. "She gave me a very wimpy answer," Blank said.)

Other projects she's aflutter about include establishing a "vulvart" gallery online. "The problem is that people don't want to buy the work, because where are they going to hang it?" she mused. "But they love looking at it." She also is working on a video she's calling "Faces of Ecstasy" - she plans, essentially, to videotape people while they have orgasms.

In addition, she's a co-housing proselytizer - spreading the word with as much verve as she has historically devoted to sex. In 1992, after 21 years in Burlingame, Blank moved into a co-housing community in Emeryville. There and now in Oakland, she has a private unit, but shares community space and some meals with residents.

"I am so many things that begin with co-. Co-housing, cooperative," she said. "The single most damaging value we have in our culture is individualism."

It's not just chatter. Blank donates a substantial chunk of her annual income - she's aiming for 50 percent one day. She also routinely makes low- interest loans to friends or worthy causes, serving as a community bank of sorts.

"We jokingly referred to it as Joani bank," said Anne Semans, who worked at Good Vibrations for 13 years. "I never took out a loan from her, but a lot of other people did."

In part, it assuages the guilt she feels for not leading a more revolutionary life, Blank said.

"Sometimes, I think it would have been neat to have done something more politically important, more radical," she said. "People say what I did was pretty radical, but it doesn't feel that way to me."

At the anniversary party, she felt proud, she said, kind of. "I don't benefit much from the credit I get," she said. "It doesn't help me when I feel insecure about anything to say, "but I started Good Vibrations.' "

In fact, her racy background sometimes is a hindrance in her latest quest: finding a mate.

"'I'm very single and unhappy about it," said Blank, who was married for 17 years - they had a ceremony but no legal papers - but has long been separated from her husband. Men in their 60s either are looking for women 15 years younger or else her past makes them jittery, she said. After a recent flirtation, the recipient of her "verbal exhibitionism" went home and did an Internet search on her name.

"You're so famous!" he sputtered when he next saw her.

She rolled her eyes: "You just found this out about me?" she said. She tried to reassure him - with mixed results.

But truly, behind all the sexual razzmatazz, what she's looking for is really quite simple, she said: a compatible soul who will share grocery shopping duties; someone whom she'll enjoy chatting with while she putters in the garden.

"People think I'm a sexual athlete or that I'll have huge, unrealistic expectations of them," she said. "I'm not that intimidating! I put my pants on one leg at a time like everyone else."

WHERE TO GO

Joani Blank's Web site is www.joaniblank.com. Good Vibrations has two retail stores in San Francisco: at 1210 Valencia St. (at 23rd Street), (415) 974-8990, and 1620 Polk St. (at Sacramento Street), (415) 345-0400, and one in Berkeley at 2504 San Pablo Ave. (at Dwight Way), (510) 841-8987. Visit Good Vibrations online at www.goodvibes.com.